Insulator.



Patented Sept. [9, I899.

Nu. 633,l75.

F. H. WITHYCOMB E.

l N S U L AT 0 R (Application filed Feb. 2, 1899.)

(No Model.)

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UNiTnn STATES PATEIT (lumen.

F "LEDERIOK HENRY \VITHYCOMBE, OF MOh' REr-ilr, CANADA, ASSIGNOR OF ELEVEN-T\VENTIETIIS TO CLEMENT HENRY MCLEOD, OF SAME PLACE.

iNSU LATQR.

SPECIFICATION forming part of Letters L'Eatent No. 638,175, dated September 19, 1899.

Application filed February 2,1899. Serial No. 704,318. No model.)

To all whom, it nuty concern/.-

Be it known that I, FREDERICK HENRY \VITHYCOMBE, of the city of Montreal, in the Province of Quebec, Canada, have invented certain new and useful Improvements in Insulators; and I do hereby declare that the fol lowing is a full, clear, and exact description of the same.

It is well known that the glass and other insulators used on telegraph and other electric lines are frequently made the targets of and are damaged by stones and other missiles. The damage resulting partially or wholly destroys their usefulness and necessitates the trouble and expense of replacing them, besides causinginconvenience by the interruption of communication.

My invention relates to the special construction of the exposed surfaces of the insu- 2o lators, apart from the general design or material employed.

My invention has for its object to render insulators less liable to breakage by providing a simple and efficient means to enable them 2 5 the better to withstand the impact of foreign bodies.

The invention consists generally in replacing the smooth outer surfaces of insulators as now made of glass, porcelain, or other in- 0 sulating material by an outer surface construction of smallprotuberanees, ridges,or depressions. These small protuberances, ridges, or intervening portions between the depressions, which may be of any desired section,

form an exterior construction which will break down readily with the impact of missiles. This breaking down of the intercepting parts cushions the blow and relieves the main portion or body of the insulator or ex- 0 tension therefrom from the full severity of the impact. It will thus be seen that the small parts, with which the missile first comes into contact offering a sufficiently less resistance than that portion of the main body or extension therefrom it is intended to protect will crush or crumble under the force of impact, and thus cushion the blow by using up a large proportion of the energy.

Experiment has proved this to be the case.

Insulators havinga numberof petticoats, whether extending horizontally, vertically, or obliquely and of proportions which render them very easy of breakage by missiles, can thus be made to offer greater resistance to fracture from those causes by forming. the exposed surfaces in the way and as herein described. Reference is made to the annexed drawing, which is an elevation,half in section,illustrating one application of the invention to one form of insulator.

The insulator shown is of the same general form as those now in use, having a central cylindrical part 1 surmounted by a dome shaped upper portion or crown 2 and having depending from it the petticoat 3. The interior is provided with the usual threads 4, adapted to screw on the end of the supporting pin, peg, or stick. The usual groove Sis provided for attaching the wire.

The insulator shown in the drawing is formed with small and therefore easily-broken protuberances (i, which may be of any desired form, (rectangular, conical, pyramidal, or cylindrical, as shown, or otherwise,) but in every case preferably of greater height than thickness and preferably arranged in oblique lines, as on the dome of the insulator, or in horizontal lines, as upon the petticoat thereof, so that the flow of moisture will in no way be impeded and yet every part of the whole of the outer or exposed surfaces be fully protected by the cushion-like protuberances. The function of such a surface formation, made up as it is of a large number of smallandeasily-crushed protuberances, is that when a missile strikes the insulator it will come in contact first with such projections, which being of a fragile or easily-broken and yielding formation will give way to the impact of the foreign body. Thus in the form shown the protuberances 0 would be first broken down. The energy of the impact will be largely expended in crushing these parts. The result will be to cushion the blow and reduce its severity as regards the main body of the insulator, and unless the impact be very severe and violent the main body of the insulator or extensions l ances adapted to form a protective cushion therefrom will be saved from fracture. I for the purpose set forth.

Having described my invention and the In testimony whereofIhave affixed my sigwayin which it is to be applied, what I claim nature in presence of two witnesses. as new, and desire to secure by Letters Pat- FREDERICK HENRY WIIIIYCOMBE. ent, is Witnesses:

An insulator the exposed surface of which FRED. J. SEARS, is composed of small easily-broken protuber- LORNE A. MACKENZIE. 

